The present invention relates to plasma processing method and apparatus for performing, with plasma, surface treatment such as patterning a thin film formed on a surface of an object to be processed represented by a substrate.
In general, when an object to be processed represented by a substrate on the surface of which a thin film is formed is subjected to a patterning process, a resist process is used. FIGS. 33A, 33B, 33C and 33D show one example of the process. In FIGS. 33A, 33B, 33C and 33D, first of all, a photosensitive resist 119 is coated on the surface of an object 106 to be processed (FIG. 33A). Next, if the resist 119 is exposed to light by an exposure apparatus and thereafter developed, then the resist 119 can be patterned into the desired configuration (FIG. 33B) Then, if the object 106 to be processed is placed in a vacuum vessel, a plasma is generated in the vacuum vessel and the object 106 to be processed is subjected to an etching process with the resist 119 used as a mask, then the surface of the object 106 to be processed is patterned into the desired configuration (FIG. 33C). Finally, by removing the resist 119 with an oxygen plasma, organic solvent, or the like, the processing is completed (FIG. 33D)
The above-mentioned resist process, which has been suitable for accurately forming a fine pattern, has come to play an important role in manufacturing electronic devices such as semiconductors. However, there is a defect that the process is complicated.
Accordingly, there is examined a new plasma processing method that uses no resist process. As a first prior art example, a plasma source that linearly generates a plasma will be described with reference to FIGS. 34 and 35. FIG. 34 shows a perspective view of a plasma processing apparatus that has a plasma source equipped with a knife-edge electrode section 109, and FIG. 35 shows a sectional view taken along the plane PP of FIG. 34. In FIGS. 34 and 35, insulating plates 110 and 111 are arranged in positions where the knife-edge electrode section 109 and the plate surfaces become mutually parallel, and gas can be supplied almost perpendicularly to an object 106 to be processed from a gas supply unit 105 via a gas passage 112. By applying a high-frequency power of 13.56 MHz to the knife-edge electrode section 109 from a high-frequency power source 108 while supplying gas from the gas supply unit 105, a plasma is generated between the plasma source including the knife-edge electrode section 109 and the object 106 to be processed, and the object 106 to be processed can be processed with the plasma. A distance b between the plasma source and the object 106 to be processed is 0.5 mm, and a width c of each of the knife-edge electrode section 109 and the insulating plates 110 and 111 is 1 mm. A width d of the gas passage 112 is 0.1 mm, and an acute angle of an edge portion e of the knife-edge electrode section is 60°. The plate surfaces of the knife-edge electrode section 109 and the plate surfaces of the plates 110 and 111 have a height f of 50 mm and a length g of 30 mm in the line direction.
Since the plasma source shown in FIGS. 34 and 35 is movable with respect to the X-, Y- and Z-axes, the object 106 to be processed can be linearly processed with the plasma over a wide range.
For example, under the conditions that He is supplied by 1000 sccm and SF6 is supplied by 10 sccm as gas to the gas passage 112 and a high-frequency power of 100 W is supplied, quartz as the object 106 to be processed can be processed with a plasma.
Next, as a second prior art example, a plasma source that generates a plasma in a hole-like shape will be described with reference to FIGS. 36 and FIG. 37. FIG. 36 shows a perspective view of a plasma processing apparatus that has a plasma source equipped with a cylindrical electrode 120, and FIG. 37 shows a sectional view taken along the plane PP of FIG. 36. Referring to FIGS. 36 and 37, the cylindrical electrode 120 is arranged in a position concentric with a cylindrical insulator 121, and gas can be supplied from a gas supply unit 105 almost perpendicularly to an object 106 to be processed via a gas passage 122 inside the cylindrical insulator 121. By applying a high-frequency power of 13.56 MHz to the cylindrical electrode 120 from a high-frequency power source 108 while supplying gas from the gas supply unit 105, a plasma is generated between the plasma source including the cylindrical electrode 120 and the object 106 to be processed, and, for example, quartz as the object 106 to be processed can be processed with the plasma. A distance b between the plasma source and the object 106 to be processed is 0.5 mm, the cylindrical electrode 120 has an outside diameter of 1 mm, and the cylindrical insulator 121 has an inside diameter of 3 mm.
Since the plasma source shown in FIGS. 36 and 37 is movable with respect to the X-, Y- and Z-axes, the object 106 to be processed can be processed with the plasma in a hole-like shape over a wide range.
For example, under the conditions that He is supplied by 1000 sccm and SF6 is supplied by 10 sccm as gas to the gas passage 122 and a high-frequency power of 100 W is supplied, the object 106 to be processed can be processed by the plasma.
Next, FIGS. 38 and 39 show a plasma processing method and apparatus as a third prior art example. FIG. 38 shows an example of a processing configuration including line processing and hole processing effected on the object 106 to be processed. In the figures, “h” represents a hole shape of a diameter of 1 mm, “i” represents a linear shape of a length (X-direction) of 40 mm and a width (Y-direction) of 1 mm, and “j” represents a linear shape of a length (Y-direction) of 30 mm and a width (X-direction) of 100 μm. FIG. 39 shows a plasma processing method and apparatus for etching a quartz substrate into a processing configuration as shown in FIG. 38. The quartz substrate was processed with a plasma in the order of (A) of FIG. 39→(B) of FIG. 39 →(C) of FIG. 39 under the aforementioned plasma conditions using the plasma sources of FIGS. 34 and 35 and FIGS. 36 and 37. In the case (A) of FIG. 39, the hole-like shape and the linear shape were concurrently processed with a plasma by means of the plasma source of FIG. 36 and the plasma source of FIG. 34, respectively. After plasma processing for about 105 sec, the plasma sources were scanned in the −X-direction to successively carry out the plasma processing. In the case (B) of FIG. 39, the linear shape was processed with a plasma by means of the plasma source of FIG. 34. Since the processing size is larger than the size of the plasma source, the plasma source was scanned in two directions of −X-direction and Y-direction. After the plasma processing (B) of FIG. 39, a processed configuration as shown in (C) of FIG. 39 was able to be formed.
However, the processing by the plasma processing methods and apparatuses described in connection with the prior art examples have had an issue that the processing size processable at a time has been disadvantageously determined upon determining the shape of the plasma source and an increasing number of plasma sources equipped with a gas supply unit and a high-frequency power supply unit have been needed as the processing configuration has become more complicated.
In view of the aforementioned conventional issues, the present invention has an object to provide a plasma processing method and apparatus capable of processing with plasma the desired arbitrary configuration (processing an object to be processed with plasma in the desired arbitrary configuration (configuration to be processed)) by a simple plasma source.